Convergence coil assembly



2 Sheets-Sheet 1 Filed March 6, 1963 67 66 INVENTOR. I gizzcezzzJPaz/ ,1TTORNEYS 2 Sheets-Sheet 2 Filed March 6, 1963 I NVEN TOR. noezz JPa zxiaa l 1 TTORNEYS United States Patent 3,188,534 CONVERGENSE COILASSEMBLY Vincent J. Patti, Norridge, Ill., assignor to Thompson RargoWooldridge, Inc., Cleveland, Ohio, a corporation of hi0 Filed Mar. 6,1963, Ser. No. 263,304 Claims. (Cl. 317-200) The present inventionrelates to an improved electromagnetic convergence assembly for acathode ray tube.

-The convergence assembly of the present invention is designed foroperation with a color kinescope of the type employing a luminescentscreen as part of a target electrode structure. Such screens includedifferent phosphor areas which produce differently colored light whenexcited by electron beam components striking the target structure fromdifferent angles, the angle of impingement determining the particularcolor of the light produced by the phosphor-areas. I

For the satisfactory operation of such kinescopes, it is necessary toeffect substantial convergence of the different electron beams at allpoints of the raster scanned by the beams at the target electrodestructure.

One commonly used type of apparatus for controlling the convergence of aplurality of electron beams at a target electrode structure includesindividual electromagnetic means located symmetrically about the axis ofthe tube neck and adjacent to the predefiection paths of the respectivebeams, and energized from the beam deflection circuit in a mannersutficient to effect the desired beam convergence. Typically, theindividual convergence electromagnets are energized by waves which areavailable from both the vertical and horizontal deflection circuitswhich provide the scanning deflection of the beams.

Since the electron guns which produce the various electron beams in acolor kinescope are symmetrically arranged about the peripheryof thetube neck, it is important that the magnetic circuits must be similarlyaligned. The difiiculty arises because the neck diameters of variouscolor kinescopes vary within substantial limits, on the order ofone-quarter inch between extremes. There is a distinct mechanicalproblem presented, therefore, in employing a particularconvergenceelectromagnetic assembly with tubes of various sizes, since it isnecessary that the magnetic circuits. retain their proper orientationwith respect to the longiudinal axis of the kinescope while stillretaining the symmetrical orientation of the magnetic structures aboutthe tube neck.

In view of these requirements, the mechanical structure for housing theconvergence electromagnets may be come quite complex andhence'expensive. Furthermore, such structures frequently"requireconsiderable assembly time, particularly in thef'r'natter of securingexternal leads to the coils.

One of the objects of the present invention is to provide an improvedconvergence coil assembly which is usable with kinescopes havingdifferent neck diameters.

Still another object of the invention is to provide a convergence coilassembly for color kinescopes which is economical to manufacture andassemble.

A further object of the invention is to provide an improved type ofhousing for convergence coil assemblies making it considerably simplerto connect external'leads 'to the coils contained Within the housing.

A further object of the invention is to provide an improved type ofhousing for convergence coil assemblies, which housing has permeabilityadjusting means accessible from the outside of the housing to vary thereluctance of the magnetic circuits contained in the housing.

A further description of the present invention will be made inconjunction with the attached sheets of drawings which illustrateseveral embodiments of the invention.

. cable In the drawings:

FIGURE 1 is a view in elevation of an improved convergence coil assemblyaccording to the present invention, illustrating the manner in which theassembly is placed about the neck of a cathode ray tube, a portion ofthe assembly being shown in completely assembled relation, another beingshown with a portion of the housing removed to show the interiorconstruction and a third portion of the assembly being shown completelydevoid of magnetic components to illustrate the configuration of thehousing section;

FIGURE 2 is a plan view of the assembly shown in FIGURE 1 lookingupwardly into the structure;

FIGURE 3 is a view similar to FIGURE 1 but illustrating a somewhatmodified form of the invention; and

FIGURE 4 is a fragmentary View of the tube engaging portion of thehousing, on an enlarged scale, and also illustrating the coupling meansby which the separate housings of the convergence coil assembly areinterlocked.

As shown in the drawings:

In FIGURE 1, reference numeral 1%) indicates generally an assembledconvergence coil assembly consisting of three identical housings 11, 12,and 13 disposed symmetrically about the longitudinal axis of the neck ofa kinescope whose neck has been diagrammatically illus trated by meansof the dashed lines 14.

Each of the housings 11, 12, and I3 is conveniently made from moldedresinous materials such as polyethylene, polystyrene, or the like. Eachof the housings is made in two sections 16 and 17 which mate along aline 18. The configuration of the section 17 is best illustrated inFIGURE 1 of the drawings, particularly in the lower left hand and lowerright hand portions. As shown in that figure, the section 17 includesopposed wall portions 19 and 21 and a base for receiving a U-shapedmagnetic core 23. A spring member 24 is bottomed on the wall 22 andurges the core 23 inwardly so that its pole faces 26 and 27 are snuglyreceived in correspondingly shaped recesses '28 and 29 provided in thesection 17. p

The legs of the core member 23 are provided with a plurality of coils oneach leg, consisting of a vertical frequency exciter coil 31 and ahorizontal frequency exciter coil 32 mounted on one leg, and acorresponding vertical frequency excitcr coil 33 and a horizontalfrequency exciter coil 34 and mounted on the opposed leg. Thecorresponding vertical frequency exciter coils 31 and 33 and thehorizontal frequency exciter coils 32 and 34 may be connected together.External connections from the coils are made by means of conductors36,37, 38, and 39 which are connected to conductors 41, 42, 43, and 44respectively. These last named conductors are part of a illustratedgenerally at reference numeral 46.

One of the features of the present invention resides in theconfiguration of the housings by which external connections to the cable46 may be made rapidly, conveniently, and inexpensively. For thispurpose, the interior structure of the housings are provided with posts47 and 48 disposed in the corners and a centrally disposed post 49 inthe area of a slot 51 formed in the section 17 to accommodate the cable46. Additional posts 52 and 53 are disposed intermediate the ends of thehousing. The posts 47, 48, 49, 52, and 53 all extend the full thicknessdimension of the two mating sections 16 and 17, that is, they arereceived snugly within suitable apertures formed in the section 16 andserve to lock the two sections together. Additional posts 54 and 56 oflesser height than the aforementioned posts are also provided to serveas wire guiding means within the housing as will be explained more fullyin the succeeding description.

For convenience in assembly, the conductors constituting the cable 46can all be cut to the same length and then portion 22 which provides aseat.

3, the bared ends can be tinned by dipping them in molten solder. Then,the conductors are slipped through the slot 51, and their lengths areadjusted by the manner in which they are led past the various posts andwall .structure within the section 17. For example, the conductor i2which must havethe longest effective length to be con:

nected with the conductorSi of the coil 32 is passed di rectly aroundthe core seat, and then between the post 52 and the inner wall of thehousing 17. The clearance provided in this space is sufficiently smallso that the conductor 42 is pinched and held against displacement by theclose fit. Conductor 41 is to be secured to the lead 36 of coil 31 isprovided with a more tortuous path to shorten the effective length. Theconductor 41 first is trained about the centrally disposed post 49, thenaround the corner post47 and about a bafile 56 extending from the innerwall of the section 17 and terminating short of the core seat; Then, theconductor is pinched between the post 54 and the inner wall of thesection 17. v

Similarly, the conductor 44 passes directly from the, slot 51 between abafiie 5'8 and the wall 21 which forms a part of the seat structure forthe magnetic core. The conductor then passes directly between the post53 and the inner wall of the section 17 where is it pinched and held inproper alignment so that it may be connected to the conductorfifiextending frorn'the coil34.

The effective length of the conductor 43 is shortened by first trainingit about'the centrally disposed post 49 then about the corner post 43,between the baftle dd and the wall 21, and then betweenthe post55 andthe inner wall of the housing 17. The conductor 43 is then at a level atwhich it can be conveniently connected to the lead 3% extending from thecoil 33.

The housings 1 1, 12, and 13 are held together ininterlockingrelationship about the neck 14 at the kinescope. For this purpose, eachof the housings is provided at one end with bifurcated-portion 61 whichis arranged to reproper alignment between the magnetic core and thelongitudinal axis of the tube neck. The structure shown in FIGURE 3differs in certain particulars from the structure or" FIGURES 1 and 2.

Where the elements are common between the two structures, however, thesame reference numerals have been applied. The difference occurs in thetype of magnetic 7 core which is employed.

In the form of the invention shown in FEGURE 3,.the magnetic coreconsists of two L-shaped pieces '72 and 73 upon which the coils 31, 32,33, and 3d are mounted. The seat provided for the core structureis alsodifi'erent in that it includes a window 7 d for the purpose of providingaccess to an adjusting disc '76 composed of ferrite or other highpermeability material, the disc 76 being urged against the abuttingsides of the core legs 5'2 and 73 by. an undulating spring '77 whichalsoserves to urge the magnetic core pole pieces 26 and 2.7 tightlyagainst the recesses 28 and 2? in the housing. Rotation of the disc 76is thereby effective to vary 2O a the reiuctance of the rnagneticcircuit. 7 v The manner of interlocking the housings 11, d2 and 13 isalso modified from the 'form shown in FIGURES 1 iand'2. -Inthis'embodiment, the housings are interlocked by providing a set of coilsprings '73 extending between angularly disposed lugs 79 on the exteriorof the housings.

From the foregoing, it will be understood that the convergence tubeassemblies of the present invention are of the kine-scope- I g *Itshould furtherbe evident that various modifications economical tomanufacture andconsiderably simplify the problems of wiring.Furthermore, they are'readily adaptable for use with kinescope tubeshaving varying neck sizes without distorting the proper alignment whichshould exist between the coil assemblies and the longiudinal axis can'bernade to the described embodiments without departing frorn theflscopeof the present invention.)

ceive a foot portion 62 of an adjoining housing in sliding 1 V relation.'The bifurcated portion dll also carries an abutment es which tends tohold the foot. portion 52 Within the bifurcated portiondl upon relativepivotal movement between the two. A C-shaped spring 64 acting betweenthe foot portion 62 and the bifurcated portion 61 tends to keepthehousings in interlocked relationship. I Eachof the housings is providedwith means accessible from the outside to vary the reluctance of themagnetic circuit existing between the magnetic coil structurecontainedin each of the housings and internal pole pieces (not shown) Within thetube neck 14. The specific adjusting means shown in FIGURE 2 consist ofa sleeve 66 which isheld in position by means of a bracket 67 secured tothe back of the section 17. The sleeve 66 receives a ferromagnetic,member 68 in sliding relation therein and the position of theferromagnetic member 68 thereby provides a means for controlling themagnetic characteristics of the coil assembly after it has been mountedonto I the tube neck.

Another feature of the present invention resides in the I configurationof the tube engaging surfaces of the housings ll, 12, and 13 toaccommodate necks of different diameter. This construction is bestillustrated in FIGURE 4 of the drawings. As evident from that figure,the tube engaging portions of the housing are composed of compound radiiincluding a centrally disposed section having a minimum radius R and thetwo adjoining portions extending outwardly from the central portion,each having a maximum radius R T he radius R is chosen to correspond tothe smallest radius tub'e'which the convergence coil assembly willaccommodate, and the maximum radius R is chosen to represent the longestradius. Tubes having radii intermediate the extremes will be engaged bythe housing where the sections of diiierent radii merge as il lustratedin reference numeral '71 in the drawings. Thus,

regardless of the size of the tube neck, the housings will always engagethe tube neck firmly while maintaining the I claim as my invention: oll. An electromagnetic convergence assembly for a cathode ray tubecomprising: v

a plurality of individual housings'disposed symmetrically about acentral axis, 7 Y spring means connecting said housings together, eachof said housings'hav'ing means for receiving a coil structure thereinand posts therein'in close proximity to the inner walls of saidhousings, a coil seated in each of said housings, electrical leads eX-tending'into said housings and connected to the-coils, at least some ofsaid posts'being spaced from said walls with a sufiiciently smallclearance so that said 3 electrical leads passing therebetween arepinched between said posts and .said'inner'walls.

I 2. A n-electromagnetic convergence assembly for a cathode ray tubecomprising;

a pluralityof individual'housings disposed symmetri-- cally abouta-central axis,=- V spring means connecting said housings together, eachof said housings having means for receiving a coil structure therein,and posts therein in close prox irnity to the innerwalls of saidhousings, a coil seated in each of said housings, electrical leadsextending into said housings and connected to'the coils,

at least some of said posts being spaced from said walls with asufficiently small clearance so that said electrical leads passingtherebetween are pinched between said posts and said inner walls,.andpermeability adjusting means accessible from outside said 5 thereofarranged to engage the neck of a cathode ray tube, said surface havingdiifering radii therealong, the shortest radius existing centrally ofsaid surface, and the larger radii existing outwardly from the center ofsaid surface.

4. In an electromagnetic convergence assembly, a coil structurecomprising:

a housing, a

means in said housing defining a seat for a coil core,

a core disposed in said seat,

a plurality of coils disposed on said core,

posts within said housing spaced about the coil seat and in closeproximity to the inner walls of said housing,

there being a sufiiciently small clearance between some of said postsand said inner walls so that an electrical conductor is pinchedtherebetween, said housing having .an arcuate tube engaging surface onthe periphery thereof,

said surface having differing radii therealong,

the shortest radius existing centrally of said surface and the largerradii existing outwardly from the center of said surface.

structure comprising:

a housing,

means in said housing defining a seat for a coil core,

a core disposed in said seat,

.a plurality of coils disposed on said core, and a ferromagnetic disc inabutting relation to said core,

said housing having a Window therethrough permitting rotation of saiddisc from outside said housing,

said housing having an arcuate tube engaging surface on the peripherythereof,

said surface having differing radii therealong,

the shortest radius existing centrally of said surface and the largerradii existing outwardly from the center of said surface.

References Cited by the Examiner UNITED STATES PATENTS 2,766,393 40/56Casey 3 l377 2,864,021 12/5 8 Lazzery 3 l7-20O 2,901,650 8/59 Barkow etal 31720O JOHN F. BURNS, Primary Examiner.

1. AN ELECTROMAGNETIC CONVERGENCE ASSEMBLY FOR A CATHODE RAY TUBECOMPRISING: A PLURALITY OF INDIVIDUAL HOUSING DISPOSED SYMMERTICALLYABOUT A CENTRAL AXIS, SPRING MEANS CONNECTING SAID HOUSING TOGETHER,EACH OF SAID HOUSINGS HAVING MEANS FOR RECEIVING A COIL STRUCTURETHEREIN AND POSTS THEREIN IN CLOSE PROXIMITY TO THE INNER WALLS OF SAIDHOUSINGS, A COIL SEATED IN EACH OF SAID HOUSINGS, ELECTRICAL LEADSEXTENDING INTO SAID HOUSINGS AND CONNECTED TO THE COILS, AT LEAST SOMEOF SAID POSTS BEING SPACED FROM SAID WALLS WITH A SUFFICIENTLY SMALLCLEARANCE SO THAT SAID ELECTRICAL LEADS PASSING THEREBETWEEN ARE PINCHEDBETWEEN SAID POSTS AND SAID INNER WALLS.